Technical Field
The present invention belongs to the technical field of preparation of inorganic nanomaterials characterized by high temperature insulation, and relates to a method for preparing a bulk C—AlN composite aerogel with high strength, and in particular, to a method for preparing a bulk C—AlN composite aerogel with high strength by using a supercritical CO2 method.
Related Art
Aerogel is a novel porous material having a nanoporous network structure formed by agglutination of colloidal particles or polymer molecules. An aerogel material has a large specific surface area, high porosity, low refractive index, low density, and high adsorbability, and has particular properties in thermotics, optics, electrics and acoustics. Especially in thermotics, the nanoporous structure of aerogel can effectively inhibit solid-state heat conduction and gas heat transfer. As a result, aerogel has excellent thermal insulation properties, and is presently known as a solid-state material having the lowest heat conductivity. Therefore, as a lightweight thermal insulation material, aerogel has board application prospects in the field of aerospace, chemical industry, metallurgy, energy-efficient buildings.
Although the aerogel material has many excellent properties, the brittleness problem and the high temperature resistant performance (greater than 1000° C.) greatly restrict its working conditions. Aluminum nitride (AlN) belongs to diamond nitrides, is stable at a temperature up to 2200° C., and has a high strength at room temperature, and the strength slowly decreases with the increase of the temperature. The AlN material is also an electrical insulator, has good dielectric properties, and is probably used as an electrical component. A C—AlN composite aerogel maintains the original excellent properties of aerogel, and the overall strength and high temperature resistant performance of aerogel are greatly improved due to doping of the AlN material, thereby further broadening the application of the aerogel material.